Inflows into reservoirs from sidearms may contain nutrient and/or pollutant particles, which are dispersed across water bodies by various transport and mixing processes including those driven by natural convection. Understanding the particle transport in reservoirs is critical as it is directly relevant to the water quality in these water bodies. This book, therefore, involves an investigation of two major themes: natural convection and particle transport in reservoirs. In reservoirs, natural convection is induced by the ambient thermal forcing including air temperature variation and solar radiation, whereas particle motion involves several fluid dynamical processes. Accordingly, understanding of the unsteady natural convection as one of the important transport mechanisms which drives particle motion in reservoirs is of great interest. The research is to understand and quantify particles transport in a reservoir model under the influence of natural thermal forcing, and should be useful to those environmental/fluid engineering professionals who want to model and understand the transport mechanism of pollutant in natural water bodies.